Field of the Invention
The invention relates to the field of methods for assisting visual exploration for individuals afflicted with a retinal pathology manifested by a scotoma, such as age related macular degeneration (ARMD), Stargardt's disease or maculopathies.
The invention relates more particularly to a method for assisting visual exploration of a digital image on a display device by an individual afflicted with a retinal pathology manifested by a scotoma.
ARMD, Stargardt's disease or maculopathies can give rise to visual deficiencies manifested by the progressive destruction of the central vision and by the development of a blind spot called a “scotoma” which deletes the information which arrives at the foveal region. This information is essential for carrying out certain daily tasks such as reading or more generally recognition of objects in an image. The absence of therapies capable of definitively eliminating this affliction compels the individual to opt for methods of assistance, often of an optical nature.
A need therefore exists to provide a method which facilitates visual exploration of an image, such as for example navigation within a text, which is able to adapt to the pathology of the individual and which uses visual neuroscience principles to best assist the individual, or indeed to increase their reading performance.
Description of the Related Art
A known solution is described in document US 2012/0200595. The system consists of smart spectacles fitted with an oculometer. If the user is an individual afflicted with ARMD, the system takes account of the zone of the individual's visual field which is masked by his/her macular scotoma. Firstly, the spectacles capture the image of a scene and project it onto ophthalmic lenses. Thereafter, the oculometer implanted on these spectacles makes it possible to measure the position of the gaze on the projected image. The user can activate the enhancement of the image zone which is masked by his/her scotoma. The enhancement of this image zone can be either the increasing of its size, or the increasing and the shifting of its lines, or a displacement and a deformation of its lines around the scotoma.
According to this system, the position of the gaze and the size of the scotoma are used to define the enhanced information in proximity to the scotoma. It is thus capable of adapting to the characteristics of each individual's scotoma. However, although the image processing proposed by this system takes account of the retinal pathology of the individual, the enhancement performed takes no account of fundamental aspects of reading in the presence of a macular scotoma. Indeed, this system acts only on the pixels of the image zone, to displace the information masked by the scotoma. Consequently, it does not make it possible to optimize the interaction between the position of the gaze, the size of the scotoma and the entities “words” and “letters” of the text. Furthermore, this system does not propose a slaving to the gaze which takes account of oculomotor events in the absence of central vision, yet this is necessary in order to optimize the ocular movements of individuals afflicted with retinal pathology. Therefore, this system risks a lack of effectiveness in terms of comfort and especially in terms of reading performance.